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A decade ago, non-radiative wireless power transmission re-emerged as a promising alternative to deliver electrical power to devices where a physical wiring proved impracticable. However, conventional "coupling-based" approaches face performance issues when multiple devices are involved, as they are restricted by factors like coupling and external environments. Zenneck waves are excited at interfaces, like surface plasmons and have the potential to deliver electrical power to devices placed on a conducting surface. Here, we demonstrate, efficient and long range delivery of electrical power by exciting non-radiative waves over metal surfaces to multiple loads. our modeling and simulation using Maxwell's equation with proper boundary conditions shows Zenneck type behavior for the excited waves and are in excellent agreement with experimental results. in conclusion, we physically realize a radically different class of power transfer system, based on a wave, whose existence has been fiercely debated for over a century.

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A 1.9-GHz CMOS differential power amplifier for a polar transmitter is implemented with a 0.18-m RF CMOS process. All of the matching components, including the input and output transformers, are fully integrated. The concepts of injection locking and variable load are applied to increase the efficiency and dynamic range of the amplifier. An asymmetric three-port transmission line transformer is proposed to embody the variable load effectively. The power amplifier achieved a power-added efficiency of 40% at a maximum output power of 32 dBm. The dynamic range was 20 dB at supply voltages ranging from 0.5 to 3.3 V. The improvement of the low power efficiency was 290% at an output power of 16 dBm.Index Terms-Class-E, CMOS, dynamic range, global system for mobile communication (GSM), injection locking, polar transmitter, power amplifier, transmission line transformer, variable load.

A 1.9-GHz CMOS power amplifier for polar transmitters was implemented with a 0.25-m radio frequency CMOS process. All the matching components, including the input and output transformers, were fully integrated. The concepts of mode locking and adaptive load were applied in order to increase the efficiency and dynamic range of the amplifier. The amplifier achieved a drain efficiency of 33% at a maximum output power of 28 dBm. The measured dynamic range was 34 dB for a supply voltage that ranged from 0.7 to 3.3 V. The measured improvement of the low power efficiency was 140% at an output power of 16 dBm.

A high BMI is not associated with increased mortality in older adults aged ≥65 years, whereas a lower BMI is associated with an increased mortality risk in later life in this population. Geriatr Gerontol Int 2018; 18: 538-546.

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